This invention relates to polypeptides that correspond to peptides encoded by the nef gene of strains of Human Immunodeficiency Virus (HIV). More particularly, this invention relates to natural and synthetic polypeptides, a diagnostic method for detecting antibodies to HIV strains in biological fluids, to a diagnostic kit for carrying out the method, and to vaccine compositions containing the polypeptides.
Acquired immune deficiency syndrome (AIDS) is a condition which is now of major importance in North America, Europe, and Central Africa. The casual agent of AIDS is believed to be a retrovirus. Recent estimates suggest that approximately 1 million Americans may have been exposed to the AIDS virus. The individuals affected show severe immunosuppression, which may be followed by the onset of fatal diseases. The transmission of the disease most frequently takes place through sexual contact, although people using narcotics intravenously also represent a high-risk group. Furthermore, a large number of individuals have been infected with this virus after receiving contaminated blood or blood products.
The isolation and characterization of the first retrovirus, known as LAV, was described in a paper by F. Barre-Sinoussi, et al. Science, 220:868-871 (1983). The use of some extracts of this virus, and more especially of some of its proteins, to detect antibodies against the virus is described in U.S. Pat. No. 4,708,818 issued to Dr. Luc Montagnier, et al.
Several isolates of the AIDS retrovirus were subsequently reported by different investigators and the isolates were referred to in the literature by different designations. It is now universally recognized that viruses previously denominated lymphadenopathy associated virus (LAV), immune deficiency associated virus (IDAV1 and IDAV2), human T-lymphotropic virus type III (HTLV-III), and AIDS related virus (ARV) are all variants of the same retrovirus. See, e.q., Nature, 313:636-637 (1985).
A subcommittee empowered by the International Committee on the Taxonomy of Viruses recently proposed that the AIDS retroviruses be officially designated as the "Human Immunonodeficiency Viruses," to be known in abbreviated form as "HIV." Isolates of human retroviruses with clear but limited relationship to isolates of HIV (for example, more than 20% but less than 50% nucleic acid sequence identity) are not be called HIV unless there are compelling biological and structural similiarities to existing members of the group.
Recently, another pathogenic human retrovirus, termed HIV-2 (formerly LAV-2), was recovered from West African patients with AIDS. HIV-2 infection is associated with an immunodeficiency syndrome clinically indistinguishable from that caused by the prototype AIDS virus, HIV-1. Clavel et al., New Eng. J. Med., 316:1180-1184 (1987). HIV-2 is related to but distinct from HIV-1 Guyader et al., Nature, 326:662-669 (1987).
Retroviruses genetically related and biologically similar to HIV have been isolated from subhuman primates. These retroviruses are designated as immunodeficiency viruses of the appropriate host species, such as simian immunodeficiency virus (SIV). SIV was first isolated from captive rhesus macaques (Macaca mulatta) at the New England Regional Primate Research Center (NERPRC). This was soon followed by a report of isolation of an SIV called STLV-III from African green monkeys. Extensive serologic cross-reactivity exists between HIV-2 and SIV.
Many of the HIV isolates analyzed have a distinct restriction map, even if recovered from the same place and time. Identical restriction maps have been observed for the first two isolates designated LAV and HTLV-3, and thus appear as an exception.
Although there is fairly wide genetic variability in the virus, the different HIV-1 strains isolated to date from American, European, Haitian, and African patients have certain common antigenic sites conserved on some proteins. This relationship has made it possible to use the prototype LAV strain as a source of antigens for detecting antibodies against all HIV-1 class viruses, in all people who carry them, regardless of their origin. Work to date has focused on the use of core proteins, envelope proteins and glycoproteins, transmembrane proteins, and fragments of these proteins as antigens in immunoassays for antibodies to HIV.
Nevertheless, the existence of multiple human immunodeficiency viruses, such as HIV-1 and HIV-2, presents a complex epidemiologic picture. Simple serologic tests that unambiguously distinguish among these retroviruses are essential for sorting out their patterns of transmission and pathogenesis. Immunoassays in which whole virus lysates are used as antigens have poor specificity due to partial cross-reactivity against conserved core antigens. Thus, there exists a need in the art for peptide antigens that have the inherent advantage of high specificity.
Moreover, there are compelling epidemiological considerations that make early detection of infection by the AIDS virus essential. Thus, for example, infection of an individual with the AIDS virus may be suspected because of the clinical symptoms manifested by the individual, but the infection may be in a very late stage before these symptoms are observed. Meanwhile, transmission of the disease may have taken place.
Finally, there is a common belief that an effective vaccine against HIV infection must be developed in order to stem the spread of the virus. Work is progressing on the development of a vaccine, but an effective vaccine has not yet been found.
In summary, there exists a need in the art for reagents, means, and methods for the detection of the AIDS virus and viruses associated with lymphadenopathies in general. The reagents, means, and methods should make it possible to detect different strains of HIV and their viral components from different isolates. Further, there is a need for reagents, means, and methods for the early detection of HIV infection. Moreover, there exists a need for pharmaceutical compositions capable of inhibiting or preventing infection of cells by HIV in vivo.